Aerospace Medicine Clinic
You are the physician on call at a ground-based, in-flight medical response agency. You receive an inbound call regarding a 67-yr-old man experiencing new-onset left-sided weakness during a 12-h transcontinental flight from South Africa to England. There are no medical personnel available on board. You are connected with the flight attendants, who collect a patient history. The patient reports an ischemic right-hemispheric stroke 2 wk ago while vacationing in South Africa. He was treated with thrombolytic therapy at that time and experienced improvement in his symptoms with only mild residual left hemibody weakness. Several hours into the flight, he experienced new worsening of his left hemibody weakness without speech impairment.
1. Which of the following is the most appropriate recommendation for commercial flight clearance after stroke?
2-wk flight restriction if functional status is appropriate.
1-mo flight restriction if functional status is appropriate.
2-mo flight restriction if functional status is appropriate.
No flight restrictions if free of symptoms.
ANSWER/DISCUSSION
1. A. The risk of stroke recurrence is about 6% within the first 90 d after initial stroke; however, about 50% of recurrences occur within the first 2 wk, suggesting decreased risk with delayed return to flight.1 Risk of recurrence can be mitigated with blood pressure control, diabetes control, cholesterol control, antiplatelet therapy, smoking cessation, decreased alcohol use, Mediterranean diet, and physical activity.2 One in-flight risk factor for recurrence is the decreased oxygen saturation at cruising altitude that could threaten susceptible tissue in the ischemic penumbra if a patient flies too soon after an ischemic stroke.3,4 Due to risk of thromboembolism as a mechanism of in-flight stroke (in the presence of patent foramen ovale), especially during long-duration flights, further considerations for stroke prevention during air travel include hydration, deep venous thrombosis (DVT) prophylaxis when appropriate, and seated leg exercises.5
Organizations such as the Aerospace Medical Association, International Air Transport Association, and The United Kingdom Civil Aviation Authority recommend waiting at least 2 wk after a stroke before unaccompanied air travel.6–8 After a period of observation to reduce risk of recurrent stroke, the most important factor for flight clearance is return of functional status, including motor, speech, and mental status clarity to navigate the commercial air travel environment.6–8 Had the patient undergone open neurosurgical intervention after stroke, there would be additional return-to-flight considerations such as the potential for pneumocephalus expansion in the low barometric pressure of the cabin or a decompressive cranial defect and its interaction with altered atmospheric pressures. In cases of craniotomy, longer time periods of 4–6 wk may be recommended, or until cleared by their primary surgeon.9 In this case, the patient improved significantly following his stroke and, aside from mild left hemibody weakness, he was otherwise able to conduct his usual activities and was cleared by a physician for international travel back to his home in England.
The patient states that his in-flight symptoms are similar to what he experienced with his stroke from 2 wk ago, with deficits more severe compared to hospital discharge. The flight attendants collected vital signs, which were unremarkable.
2. Which of the following in-flight exam findings would most likely indicate an ischemic rather than hemorrhagic stroke?
Seizure.
Altered mental status.
Symptom improvement with supine positioning.
Symptom worsening with supine positioning.
ANSWER/DISCUSSION
2. C. In this patient with recent stroke, recurrent stroke is high on the differential, but the etiology remains unknown without imaging capabilities to determine ischemic or hemorrhagic etiology. Ischemic and hemorrhagic stroke treatments may conflict with one another, particularly for blood pressure management, and physical exam findings could potentially help elucidate etiology and guide management decisions. For example, hemorrhagic strokes are more likely to present with acute headache, seizure, altered mental status, and gaze impairment.10 Overall, strokes account for approximately 2% of in-flight medical emergencies.11 In a regular terrestrial setting, the most common cause of ischemic stroke is cardioembolic.12 In aviation, however, the most common cause of in-flight ischemic stroke has been reported to be atherothrombosis in the setting of carotid stenosis, although traveler’s thrombosis and arterial dissection are also potential etiologies.13 Traveler’s thrombosis refers to the elevated risk of DVT during long-duration flight, which may embolize and cause stroke, often in association with patent foramen ovale.14,15 In this patient on a long-duration flight >7 h, risk of DVT is over 3.6%, so evaluation for signs and symptoms of DVT may be considered as part of his stroke workup.15
Blood pressure augmentation recommendations are different depending on stroke type, where ischemia is managed with permissive hypertension while hemorrhage is managed with antihypertensive therapies. In addition to medical therapy, patient positioning can augment cerebral blood flow, where head of bed position may have both therapeutic and diagnostic benefits in distinguishing stroke etiology. Supine position increases cerebral perfusion and blood pressure, which has the potential to improve symptoms in ischemic strokes, but it could also worsen hemorrhagic stroke. Because 80% of strokes are ischemic and only 20% are hemorrhagic, some studies suggest prehospital flat positioning could improve outcomes on a population basis for patients with undifferentiated stroke.16 However, current guidelines recommend at least 30° head positioning during prehospital stroke transport to protect the airway and prevent risk of aspiration.17
In this patient with a history of ischemic stroke, possibilities include both hemorrhagic conversion of his prior stroke territory or recrudescence of his prior ischemic stroke. The rate of hemorrhagic conversion may be slightly higher than the rate of recurrent stroke, both of which have highest incidence in the first 2 wk after stroke onset.18 The Siriraj or Besson scoring systems could be used to help dichotomize exam, history, and vitals findings into likelihood of ischemic vs. hemorrhagic stroke.19 Given the patient’s absence of headache, altered mental status, and hypertension, supine position may be considered to determine whether symptoms are perfusion-dependent and improve, if deemed safe from an aspiration and airway standpoint. While there is no currently available modality to detect stroke and distinguish ischemic vs. hemorrhagic in flight, there are several emerging technologies in development.20 These include blood testing for glial fibrillary acidic protein, portable ultra-low-field MRI, eddy current dampening, and microwave-sensing helmets.20,21 Future deployment of these emerging technologies to resource-limited settings such as air travel could help guide early stroke management. One of the most common causes of in-flight neurological symptoms is vasovagal syncope, where supine position is also beneficial for treatment by supporting brain perfusion after a hypotensive episode.22 However, in this patient with retained consciousness and persistent symptoms, a vasovagal episode is unlikely. In this case, the patient remained in the upright seated position and symptoms remained unchanged.
3. Which of the following in-flight therapies should be recommended?
Aspirin 325 mg.
Supplemental oxygen.
Systolic blood pressure (SBP) <140 mmHg.
Benzodiazepine.
ANSWER/DISCUSSION
3. B. Medical therapies available for neurological conditions in international flight typically include antiepileptic/sedatives, pain relievers, antiemetics, antiplatelets, and antihypertensives. While antiepileptics/benzodiazepines are often available for international flights, they are not typically available for domestic flights in the United States. In this case, supplemental oxygen is warranted if available in flight, especially considering the potential etiology of hypobaric hypoxia exacerbating the susceptible brain tissue from this patient’s recent stroke.13
Given that thrombolytics are currently unavailable on board, one might consider the use of aspirin for a prehospital stroke. While the odds of an undifferentiated stroke favor ischemic etiology, a clear benefit of urgent aspirin administration has not been demonstrated in a prehospital setting, and administration could significantly worsen a hemorrhagic stroke. Aspirin therapy after stroke has shown most benefit for preventing recurrent stroke rather than improving the incident stroke.23 For these reasons, aspirin therapy is not typically recommended for undifferentiated prehospital stroke.24
SBP <140 mmHg could be beneficial in hemorrhagic stroke, although it would not be warranted in this patient with undifferentiated stroke. In this case, probability may favor ischemic injury where management includes permissive hypertension. The INTERACT-4 clinical trial evaluated prehospital blood pressure reduction in undifferentiated stroke and found no benefit of lowering SBP <140 mmHg, likely due to the higher prevalence of ischemic stroke. Ischemic strokes have a management target of <220 mmHg in the absence of thrombolysis and <185 mmHg in the presence of thrombolysis.25 As such, these could represent maximum parameter thresholds for treatment target in this case, although optimal blood pressure management of prehospital stroke has yet to be clarified in the literature.26
Cerebrovascular disease is the most common cause of adult-onset seizures, where about 6% of stroke patients have post-stroke seizures, most of which occur within the first week after stroke.27 Furthermore, hypobaric hypoxia that occurs at high altitude can increase seizure susceptibility.28,29 For example, prior studies have shown that air travel is associated with increased postflight seizure frequency in patients with epilepsy.30 As such, seizure is on the differential for this patient with a known recent stroke. However, in the absence of other signs such as altered mental status or gaze deviation, we would recommend monitoring without a benzodiazepine. Administering benzodiazepines could complicate airway patency in flight, especially in the case of neurological decline.
4. Which of the following diversion recommendations should be made for this flight?
Divert to Accra, Ghana, where endovascular resources are unlikely (∼3 h).
Continue to England, where endovascular resources are likely (∼6 h).
Return to South Africa, where endovascular resources are likely (∼6 h).
In-flight aspirin therapy and follow-up with primary care physician in England.
ANSWER/DISCUSSION
4. B. Time from symptom onset is one of the most important determinants of stroke management. For example, thrombolytic therapy typically has a time window of 4.5 h, while mechanical thrombectomy has a time window up to 24 h. Beyond these timeframes, stroke management typically includes observation and modification of chronic risk factors. In this case, the decision for flight diversion is multifactorial, hinging on treatment resources and specialists that are available within limited timeframes.31 For example, a diversion to Accra (∼3 h) may enable thrombolytic therapy without endovascular capability, while continuing to England (∼6 h) could enable endovascular therapy at the expense of missing the thrombolytic window.
Thrombolytic guidelines are an important consideration in this decision making. American Heart Association guidelines recommend against thrombolysis in early recurrent stroke within 3 mo; however, a recent meta-analysis suggests no increased risk of adverse outcome.32,33 Similarly, repeated administration of thrombolysis has shown elevated risk of hemorrhage when given within 2 wk but could be safe within 3 mo.34–36 Should the patient be considered a candidate for repeat thrombolysis, the etiology of large vs. small vessel occlusion may be an important decision factor. Thrombolysis has a high likelihood of failure in large vessel occlusion, where as low as 10% of patients achieve recanalization.37 In these cases, mechanical thrombectomy would still be desired, which may favor direct transport to an endovascular center. In this patient with isolated motor deficit and absence of other cortical signs such as neglect, sensory symptoms, confusion, or gaze deviation, a large vessel occlusion would be unlikely according to the 3-Item Stroke Scale score.38 This suggests that urgent diversion to the closest stroke center would be most appropriate.
In a terrestrial setting, emergency medical services often must decide between transport to a closer primary stroke center (thrombolytic capable) or to a further comprehensive stroke center (endovascular capable). Consensus guidelines suggest direct transport to a comprehensive stroke center only if it is within 60 min of the nearest primary stroke center.39 In this case of transcontinental flight, the nearest comprehensive stroke center was felt to be approximately 3 h longer than transport to a primary stroke center, but the proximity to the thrombolytic window was felt to favor direct transport to the comprehensive stroke center. Some authors have suggested airline passengers are more likely to receive acute stroke treatment due to increased awareness and triaging of in-flight stroke symptoms; however, timely thrombolysis in this transcontinental flight with limited diversion options was unlikely.40
Discussion of risks and benefits was conducted with the passenger and he indicated preference for transport to the hospital most likely to provide therapeutic intervention. With 3 h left in the flight until Accra, it was felt that the patient would be unlikely to arrive at a local hospital within the 4.5-h thrombolytic window and would likely only be observed with supportive care. Despite missing the thrombolytic window by continuing to England, the patient would remain within the thrombectomy window for definitive management. For these reasons, recommendation was made to continue to England. The passenger tolerated the flight and remained stable without further deterioration. Upon arrival, he was transported to a hospital in the United Kingdom for definitive care. As the standard of care has evolved in stroke management, this case highlights the importance of flight surgeons and support staff in maintaining up-to-date education and the risk/benefit analysis of complex medical decisions with limited resources.
Mampre D, Kelbert J, Rupp C, Alves P, Stabenau K, Lindgren J, Petersen E. Aerospace medicine clinic: a case of recurrent stroke on an international flight. Aerosp Med Hum Perform. 2025; 96(12):1099–1102.
